Pharmacokinetics (Week 2) Flashcards
what is pharmacokinetics?
relates to how a drug gets to its target.
what are the 4 key processes of pharmacokinetics?
(ADME)
1. Absorption
2. Distribution
3. Metabolism
4. Elimination
what are the routes of administration?
enteral (thru the GI tract; i.e., oral, rectal)
parenteral (not thru GI tract; i.e., injection, inhalation, topical, mucosal, sublingual)
what are the requirements for oral administration?
water-soluble resistant to stomach and liver enzymes (first-pass metabolism), and at least partially lipid soluble.
what is cMAX?
Highest level of concentration in
blood
what is bioavailability?
% of drug in the system.
what occurs in the process of distribution?
Once in the bloodstream, the drug travels throughout the body until it reaches its target (receptor)
what is the fenestra?
the place where drugs exit capillaries through small pores
what is the blood-brain barrier?
Combination of “tight junctions” of capillary
endothelial cells (no fenestra) and “astrocytic sheath”
what is a drug half life?
the time it takes for the amount of a drug’s active substance in your body to reduce by half
what is steady state concentration?
Consistent level of drug in
body achieved by repeated,
regular-interval dosing
what is drug tolerance?
A progressive decline in response with
repeated usage of a drug
what is drug dependence?
Administration of drug is required to avoid
withdrawal symptoms
Drugs administered “sublingually” (under the tongue) and drugs administered orally are absorbed mostly in the ____________ and ____________, respectively.
mouth; small intestine
Which route of administration is characterized as “enteral”?
oral
What drug attributes decrease the likelihood of drug absorption?
high water solubility, large size, low lipid solubility.
What are the two main difference between capillaries in the periphery and capillaries in the brain?
Capillaries in the brain have tighter junctions and are surrounded by membranes of astrocyte cells
Which is the most dangerous mode of drug administration?
intravenous
The degradation of drugs by enzymes present in the gastrointestinal tract and liver is known as
first-pass metabolism.
Most drugs are excreted via the
kidneys
The time for the plasma level of a drug to fall by 50% is called the
elimination half life.
The “steady-state” concentration of a drug (the stable level achieved in blood with repeated, regular dosing) is
achieved when the amount of drug administered per until time equals the amount eliminated per unit time
The ability of liver enzymes to degrade a drug more efficiently in the continued presence of the drug is termed
metabolic tolerance.
